I know there is a lot of great vehicle knowledge here. I am engine illiterate. I just poured about a 1/4 or less of a jug of windshield wiper fluid into the coolant reservoir of my wife's Subaru. As of this writing, I have not conveyed that information to her and let her drive off to work. I'm ascared, not because of what might happen to her engine, but what might happen to me if she finds out I screwed up her car. Does her system need to be flushed and refilled?